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23 Αυγ 2021 · For example, in a molecule of water, with hydrogen covalently bonded to oxygen, the electrons are “pulled” toward the oxygen, which is more electronegative. Because of this, there is a slightly greater negative charge near the oxygen atom of water, compared to the hydrogen (which, correspondingly has a slightly higher positive charge).
We develop our understanding of electronegativity-based arguments about bonds and molecular interactions by comparing the electronegativities of two atoms. Recall, the larger the electronegativity, the stronger the "pull" an atom exerts on nearby electrons. We can consider, for example, the common interaction between oxygen (O) and hydrogen (H).
When the sharing of electrons between atoms is equal, such as O 2 (oxygen) or CH 4 (methane), the covalent bond is said to be nonpolar. However, when electrons are shared, but not equally due to differences in electronegativity (the tendency to attract electrons), the covalent bond is said to be polar.
Key Points. The difference in electronegativities between oxygen and hydrogen atoms creates partial negative and positive charges, respectively, on the atoms. Water molecules attract or are attracted to other polar molecules. Molecules that do not dissolve in water are known as hydrophobic (water fearing) molecules.
For example, water (H2O) is polar due to the difference in electronegativity between oxygen and hydrogen, while methane (CH4) is nonpolar because carbon and hydrogen have similar electronegativities, resulting in an even distribution of charge.
18 Μαΐ 2021 · The ability of an atom in a molecule to attract shared electrons is called electronegativity. When two atoms combine, the difference between their electronegativities is an indication of the type of bond that will form.
Definition: Electronegativity. Electronegativity measures how strongly an atom attracts an electron pair (or electron pairs) from a chemical bond. Let’s consider a molecule of water. Oxygen is more electronegative than hydrogen. So, the electrons of the covalent bonds are closer to the oxygen atom and further from the hydrogen atoms.
